Field Map; Fig . 20: Field Current Relative To Armature Current - Curtis Instruments MultiMode 1243 Generation 2 Manual

Field current
Fig. 20
relative to armature
current, with field map
parameter set at 50%
and 20%.
Curtis 1243 2 Manual
GEN

FIELD MAP

The field map defines the relationship between armature current and field
current under steady-state drive conditions. The shape of the field map is
determined by the programmed Field Min, Field Max, Field Map, Field Map
Start, and M1-M4 Drive C/L settings.
As shown in Figure 20, the field map parameter adjusts the field current
at the Field Map Midpoint, which is located halfway between the programmed
Field Map Start and the programmed M1-M4 Drive C/L. With the field map
parameter set at 50%, the motor's field current increases linearly with increasing
armature current—thus emulating a series wound motor.
Field Max
Field Map
(50%)
Field Min
0
0
Field Map Start
Field Max
Field Map
(20%)
Field Min
0
0
Field Map Start
Decreasing the field map parameter reduces the field current at a given
armature current. As the field current is reduced, the motor will be able to
maintain speeds closer to the maximum speed value as its load increases;
however, the motor's capability to produce torque at these higher speeds will
decrease. With the Field Map reduced to 20%, the field current at the Field
Map Midpoint will exceed Field Min by 20% of the range between Field Min
and Field Max.
The field map parameter is tuned as part of the vehicle performance
adjustment process (Section 5).
3 — PROGRAMMABLE PARAMETERS:
Field Map Midpoint
ARMATURE CURRENT
Field Map Midpoint
ARMATURE CURRENT
Field Parameters
100%
Drive C/L
100%
Drive C/L
39